Space Parachutes

I've been thinking about reusable launch vehicles
and parachutes lately:

"http://www.geocities.com/launchreport/weblog.html"

- Ed Kyle

"Ed Kyle" wrote in message
oups.com...
I've been thinking about reusable launch vehicles
and parachutes lately:

"http://www.geocities.com/launchreport/weblog.html"

- Ed Kyle


This one is a cheap GPS guided parachute landing system:
http://www.mmist.ca/

And this one is a pneumatic muscle actuator for parachutes, enabling
near zero landing velocity and the use of much smaller parachutes:
http://www.vertigo-inc.com/air_drop_.../pma/pma.shtml

Pete.

"Ed Kyle" wrote in message
oups.com...
I've been thinking about reusable launch vehicles
and parachutes lately:

"http://www.geocities.com/launchreport/weblog.html"

- Ed Kyle

So, what would happen if you jumped off the shuttle in orbit toward the
earth with parachute? Could you slow down enough to keep from burning up?
Since the space suit is good for 8 hours it should be plenty of time to
freefall to earth.

Nog wrote:
"Ed Kyle" wrote in message
oups.com...
I've been thinking about reusable launch vehicles
and parachutes lately:

"http://www.geocities.com/launchreport/weblog.html"

- Ed Kyle

So, what would happen if you jumped off the shuttle in orbit toward the
earth with parachute? Could you slow down enough to keep from burning up?
Since the space suit is good for 8 hours it should be plenty of time to
freefall to earth.

There was a 1960s concept called MOOSE (Man Out of Space
Easiest) like this. It would have been a personal
reentry system with a small heat shield that used a
parachute for the final landing. Here's a story at:

"http://www.space.com/news/spacehistory/moose_000923.html"

Today, some folks are thinking about a new sport, called
"spacediving", where the enthusiast thrillseeker could
ride a suborbital rocket to the edge of space and then
*BAIL OUT*. See, for example:

"http://www.canadianarrow.com/spacediving.htm"

- Ed Kyle

On 11 Aug 2005 07:28:10 -0700, "Ed Kyle" wrote:

There was a 1960s concept called MOOSE (Man Out of Space
Easiest) like this. It would have been a personal
reentry system with a small heat shield that used a
parachute for the final landing. Here's a story at:

"http://www.space.com/news/spacehistory/moose_000923.html"

Today, some folks are thinking about a new sport, called
"spacediving", where the enthusiast thrillseeker could
ride a suborbital rocket to the edge of space and then
*BAIL OUT*. See, for example:

"http://www.canadianarrow.com/spacediving.htm"

I was wondering when someone would get around to that. Kind of like
the ending of the movie "Dark Star".

You just have to wonder what it would be like to come down from orbit
riding a surf board. The biggest question is if you would actually
survive, with additional steps taken of course.

I guess that half of this answer has to do with your orbital velocity,
when like the Shuttle does mach 24 due to having lots of sideways
instead of upwards.

Like in this latest Shuttle reentry it did its deorbit burn North of
Madagascar, reentered the atmosphere over New Zealand, then finally
came down in California. So it took about half of the entire planet
just to touch down.

Anyway, I have always thought that if you made your surf board
suitable to reenter the Earth's atmosphere, then it does in fact seem
possible to make it safely to the ground.

The rider would certainly have one very interesting and dangerous ride
though, which could easily prove to be fatal.

This latest idea of course only does so from the sub-orbital altitude,
with very little sideways motion. So it is indeed safe enough for your
usual extreme sports idiots to have some fun.

I await the day when someone is indeed insane enough to ride all the
way down on a (modified) surf broad.

Cardman.

Pete Lynn wrote:
"Ed Kyle" wrote in message
oups.com...
I've been thinking about reusable launch vehicles
and parachutes lately:

"http://www.geocities.com/launchreport/weblog.html"

- Ed Kyle


This one is a cheap GPS guided parachute landing system:
http://www.mmist.ca/

And this one is a pneumatic muscle actuator for parachutes, enabling
near zero landing velocity and the use of much smaller parachutes:
http://www.vertigo-inc.com/air_drop_.../pma/pma.shtml

Thanks for the links. I originally mentioned Irvin
Aerospace "http://www.airbornesystems-na.com/main.html"
who makes the Falcon 1 and Kistler K1 parachutes. I've
now added a link to Pioneer Aerospace
"http://www.pioneeraero.com/homepage.htm" builds the RSRB
chutes and developed the Mars Exploration Rover parachute
systems.

- Ed Kyle
"http://www.geocities.com/launchreport/weblog.html"

"Allan Cole" wrote:

So, what would happen if you jumped off the shuttle in orbit toward the
earth with parachute? Could you slow down enough to keep from burning up?
Since the space suit is good for 8 hours it should be plenty of time to
freefall to earth.

The burn on reentry is only caused by an object entering the atmosphere at a
high speed. If you floated down gently, you wouldn't feel any heat at all.

True, but there are two problems you're not addressing. First, an
object in orbit around the Earth is necessarily at high speed. (To slow
to a halt so you can "float down gently" would require as much
acceleration as it did to get to orbit in the first place.) Second,
dropping straight down through the upper atmosphere isn't going to
provide much resistance until the air gets somewhat thicker...by which
time you're going at a very high speed.

So, what would happen if you jumped off the shuttle in orbit toward the
earth with parachute? Could you slow down enough to keep from burning up?
Since the space suit is good for 8 hours it should be plenty of time to
freefall to earth.

The burn on reentry is only caused by an object entering the atmosphere at a
high speed. If you floated down gently, you wouldn't feel any heat at all.

"Nog" wrote in
:


"Ed Kyle" wrote in message
oups.com...
I've been thinking about reusable launch vehicles
and parachutes lately:

"http://www.geocities.com/launchreport/weblog.html"

- Ed Kyle

So, what would happen if you jumped off the shuttle in orbit toward
the earth with parachute?

1 - You're still in orbit.
2 - Orbital decay will slowly bring you to a slighter denser amosphere. At
ISS's altitude, about 60 meters per day).
3 - Sooner or later the orbital decay will force you to enter a denser area
at too much speed and burn, but it's OK since you've died by asphixiation 8
hours after step #1.
4 - Someone will add 10 pages to the astronouts manual to the effect that
"Thou Shall Not Jump".


Could you slow down enough to keep from burning up?
No. At the altitude you'd need the parachute, you're still going
hipersonic enough to rip a parachute to shreds. Unless it's the size of a
football field, which would probably would kill you from opening shock.


Since the space suit is good for 8 hours it should be
plenty of time to freefall to earth.
An orbit is nothing more than the path of freefall "towards" earth.


--
Doing AIX support was the most monty-pythonesque
activity available at the time.
Eagerly awaiting my thin chocolat mint.

Interesting question.

Let us assume that you have some way to do a reentry burn (handheld
solid rocket?) so that you can lower the perigee of your orbit into the
atmosphere and that you could somehow unfold the parachute while still
in vacuum.

AFAIK, a body with a very large surface per unit mass sees the same
acceleration profile as a more dense body, just much higher in the
atmosphere. So one can assume a similar acceleration profile as with a
ballistic reentry.

You would feel the first deceleration much higher than ordinary
spacecraft, maybe at an altitude of 130km. The initial small
deceleration would cause the parachute to completely unfold. Assuming
the parachute and the astronaut survives further, you would see 8 to 10
gs of maximum deceleration.

The good thing is that you see this deceleration high up in the
atmosphere and that the kinetic energy of the orbiting mass gets
dissipated over a large area. One problem is that the feet of the
astronaut would be the first object to intercept the (very low density)
hypersonic airflow, so you would probably need a small (0.4m diameter)
hemispherical heat shield for the feet.

Another problem would be that the parachute would have to be so far
behind the astronaut that it does not intercept the shock wave caused
by the foot heatshield.

But on the whole, it seems possible that a specially constructed
parachute made of heat resistant material and a modified EVA suit would
survive reentry.

I hope that some day somebody will try this

regards,

R=FCdiger